This invention relates generally to the analysis of a liquid sample, and especially to biomedical analysis of a body fluid such as a dialyzed body fluid.
As illustrated by U.S. Pat. No. 4,633,878 to Bombardieri, the use of a sensor to determine the concentration of a target chemical species in a liquid sample provided by a separator device such as a hollow fiber membrane, and to communicate the concentration data to a microprocessor, is known. As exemplified by U.S. Pat. No. 4,897,189 to Greenwood et al, a piston driven by a microprocessor-controlled motor, is known for pressure-compressing a compartment containing a liquid, to drive the liquid from the compartment. Additionally, as illustrated by U.S. Pat. No. 4,863,454 to LaBove, it is known to join a pair of containers with a flow connector in between, and to, by force of gravity, pass the contents of one container into the other.
However, there is a need for improved analytical apparatus useful in the analysis of a small liquid sample for a target chemical species. Such apparatus would beneficially provide for the preparation of an analyzable product, suitably a colorimetrically analyzable product, from the target species, and provide for quantitative analysis. Advantageously, such apparatus would be capable of controlling the preparation of the analyzable product, of analyzing the product, and of informing a user as to the analytical value obtained. Such apparatus would be especially beneficial for monitoring urea concentration during dialysis.